Wireless communication systems have become very important in recent years. Most commercial and public-safety organizations need wireless communications. The importance of wireless communication is even more increased in emergency situations. For example, the police department requires efficient communication between different Portable Subscriber Units (PSUs) allotted to patrolmen, detectives, etc. Similarly, other agencies such as fire departments, transportation departments, water departments, etc., also require similar effective communication services.
However, utilization of PSUs for accessing communication services is often limited by the coverage and signal strength at the location of the PSUs. For example, a user can carry a PSU into the basement of a building, which may weaken the strength of the signal received by the unit. Further, the user can get a limited signal, or absolutely no signal, at a remote location such as the outskirts of a town or a city. There are also times when the communication link between a base station and the PSU is degraded or lost completely. The base station facilitates communication sessions between multiple PSUs in a particular area.
Various techniques are employed to provide wider coverage to PSUs in areas where the coverage provided by the fixed system is insufficient. One such technique utilizes mobile Vehicular Repeaters (VRs) to provide enhanced signals to PSUs. A VR installed in a vehicle includes an external antenna, which receives a signal from the base station, amplifies it, and sends the amplified signal to an internal antenna of the VR. The VR then sends the amplified signal to the PSU registered with the VR, thereby enabling the PSUs to maintain continuous communication.
If communication through a VR breaks down, the PSUs switch over to other mobile VRs available in their vicinity. However, this results in failed communication in the event of other VRs not being available in the vicinity of the failed VR. Therefore, there is a need for a method and system for providing coverage to PSUs when communication through a VR has failed.
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